@SuppressWarnings("unused")
	@Deprecated
	private static boolean connectServer(String ip, int port, String username, String password, FTPClient ftpClient) {
		/**
		 * 1、先连接ftp服务器
		 */
		try {
			ftpClient.connect(ip, port);
			/**
			 * 2、登陆
			 */
			if (!ftpClient.login(username, password)) {
				logger.error("登陆服务器失败......");
			}
			// ftpClient.getSystemType();
			/**
			 * 使用本地的主动模式（默认为本地被动）
			 */
			// ftpClient.enterLocalActiveMode();
			/**
			 * 二进制传输
			 */
			ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
			/*
			 * if(FTPReply.isPositiveCompletion(ftpClient.sendCommand(
			 * "OPTS UTF8", "ON"))) {
			 * BaseEntity.getInstance().setLocalCharset("utf-8"); }
			 */
			ftpClient.enterLocalPassiveMode();// 设置被动模式

			ftpClient.setControlEncoding(BaseEntity.getInstance().getLocalCharset());
			/**
			 * 每隔2分钟发送一次请求，没有任何意义的请求，保持连接畅通
			 */
			ftpClient.setControlKeepAliveTimeout(300);
			ftpClient.setControlKeepAliveReplyTimeout(300);
			ftpClient.setKeepAlive(true);

			ftpClient.setDefaultTimeout(10000);
			ftpClient.setConnectTimeout(10000);
			ftpClient.setDataTimeout(10000);
			// 外网需要设为false
			ftpClient.setRemoteVerificationEnabled(false);
			// ftpClient.setUseEPSVwithIPv4(true);
		} catch (IOException e) {
			if (ftpClient.isConnected()) {
				try {
					ftpClient.disconnect();
				} catch (IOException f) {
				}
			}
			e.printStackTrace();
			logger.error("不能连接到  " + ip + ":" + port + " 服务器，或者使用账号：" + username + "，密码：" + password + " 无法登陆", e);
			return false;
		}

这是后来的代码

private static boolean getConnect(String ip, int port, String username, String password, FTPClient ftpClient) {
		/**
		 * 1、先连接ftp服务器
		 */
		try {
			logger.info("连接ftp服务器");
			ftpClient.setDefaultTimeout(10000);
			ftpClient.setConnectTimeout(10000);
			ftpClient.setDataTimeout(10000);

			ftpClient.connect(ip, port);
			/**
			 * 2、登陆
			 */
			logger.info("登录ftp服务器");
			if (!ftpClient.login(username, password)) {
				logger.error("登陆服务器失败......");
			}
			// ftpClient.getSystemType();
			/**
			 * 使用本地的主动模式（默认为本地被动）
			 */
			// ftpClient.enterLocalActiveMode();
			/**
			 * 二进制传输
			 */
			logger.info("设置ftp属性");
			ftpClient.enterLocalPassiveMode();// 设置被动模式
			ftpClient.setControlKeepAliveTimeout(300);
			ftpClient.setControlKeepAliveReplyTimeout(300);

			ftpClient.setFileType(FTP.BINARY_FILE_TYPE);
			ftpClient.setControlEncoding(BaseEntity.getInstance().getLocalCharset());
			ftpClient.setKeepAlive(true);
			// 外网需要设为false
			// ftpClient.setRemoteVerificationEnabled(false);
		} catch (IOException e) {
			if (ftpClient.isConnected()) {
				try {
					ftpClient.disconnect();
				} catch (IOException f) {
				}
			}
			e.printStackTrace();
			logger.error("不能连接到  " + ip + ":" + port + " 服务器，或者使用账号：" + username + "，密码：" + password + " 无法登陆", e);
			return false;
		}

		return verifyFtpConnect(ftpClient);
	}

 /**
     * Set the default timeout in milliseconds to use when opening a socket.
     * This value is only used previous to a call to
     * {@link #connect connect()}
     * and should not be confused with {@link #setSoTimeout setSoTimeout()}
     * which operates on an the currently opened socket.  _timeout_ contains
     * the new timeout value.
     * <p>
     * @param timeout  The timeout in milliseconds to use for the socket
     *                 connection.
     */
    public void setDefaultTimeout(int timeout)
    {
        _timeout_ = timeout;
    }